Weird ethernet thing

[David Goetzka]

I'm helping a friend troubleshoot a problem he's having. He uses Mac's 
exclusively in his company. Everything from Beige G3's to the latest 
PowerMac G4 towers running some with Mac OS 9.2.2 and most running 
10.2.6. He also has 3 cubes. Every Mac in the shop connects to his 
4-Sight Fax server with no problems. One of the Cubes can connect, but 
it is running 9.2.2. The other two Cubes are running Jaguar and can't 
connect and receive faxes. I can send faxes, but can't receive. As a 
side note, the software is Java based.

At first I thought it's a half-duplex or full-duplex issue. I manually 
changed from half to full and from TX to UDP using ifconfig in the 
terminal. This didn't help.

I have the Console running and enabled logging and can watch the 
4-Sight client software trying to connect, but never does connect.

4-Sight has been little help. They don't have a Cube to test the 
software on, so they basically said that if I send them a Cube, they 
will test it when they get around to it. My friend loves his Cubes and 
doesn't want to scrap them and get something else like an iMac or eMac.

I've scoured the internet for more info on this, but haven't had much 
luck. One of my favorite sites (macosxhints.com) had a posting where a 
user had a problem connecting to a service and solved the problem by 
using ifconfig to change the MTU (maximum transmission unit) from the 
default of 1500.

Again, 4-Sight works on all Macs except the 2 Cubes running Jaguar. All 
the Cubes have the same firmware and or stock 450 MHz with the 
exception of video, ram, and hard drive upgrades. They are running the 
latest versions of Java. All the Cubes connect to all other services on 
the network and can file share, surf and email with no problems.

Has anybody on the list seen weird networking issues with other 
programs and successfully fixed them?

Thanks in advance.

David